Safety apparatus



April 27 1943- L.. L WEAVER 2,317,836

SAFETY APPARATUS Filed May 7, 1941 FIG. 4A

A TTOPNEV` Patented Apr. 27, 1943 IUNITED sTATEs PATENT OFFICE I samllmsi I Leo L. Weaver, Cranford, N. J.; assignor .to

Western Electric Company, Incorporated, New York, N. Y., a corporationof New York ammunition May '1, 1941, semi 10.392.332

against explosively dangerous vapors. A

There are innumerable instances in industry where it is necessary tostore in temporary or more or less permanent fashion materials whichwill produce or give off inflammably explosive gases or vapors,especially if abnormal/conditions become accidentally created in theirimmediate environment. Thusfor example, a great variety of mixturescomprising, alone or with other ingredients, a solid such as celluloseacetate softened or dissolved in an inflammable volatile liquid such asacetone, are used in many ways in various arts. In particular, in theart of manufacturing insulated electrical wire, a thickish solution,dispersion or paste of cellulose acetate inv acetone with otheringredients isused to coat wire, either bare orrhavlng a sheath ofinsulation thereon to which the cellulose acetate-acetone mixture isapplied.

Such mixtures are ordinarily made up and held in some kind of storagetank or receptacle. The mixture may be made up in or'suppliaed to thetank in batches intermittently, as itis used up; or, in some cases, itmay be made up continuously at the rat'e at which it is being used. Ineither case it is generally preferable to have a substantial pool of themixture to draw from in order to ensure constancy of protection ofingredients in the mixture, and this pool'wiil be kept in a storage orsupply tank or other container. Under normal atmospheric conditions,particularly of temperature, the evolution of vavpors from the materialin the tank will be insuiilclent to create any hazard not to becontrolled by ordnary means. However, lf abnormal conditions arise, e.g. an abrupt and considerable rise 1n temperature such as might beoccasioned by a fire in the building or by the rupture of an adjacentsteam line or otherwise, there may occur a relatively enormous evolutionof vapor, even enough to burst the tank and to liberate the vapors intothe outer air. Being easily infiammable and also capable of makingviolently explosive mixtures with air, such circumstances are obviouslyhazardous.

An object of the 4present invention is to provide means whereby sucnhazards may be greatly d mlnished and even substantially prevented, tnemeans being set in operation by the circumstances which tend to create.the hazard..

Wits the above and other objects in view the invention may he embodied,in connection with a receptacle to hold material tending to producedangerous vapors and having a normally closed explosion relief aperturetherein, in means to open the relief aperture and simultaneously tosmother and dilute vapors issuing therefrom with a, non-inflammableexplosion preventing gas, the said means being actuable by a devicepositioned Within the receptacle and set in ac-4 tion by the occurencetherein of an abnormal condition. l

Other objects and features of the invention will appear from thefollowing detailed description of one embodiment thereof taken inconnection With the accompanying drawing in which the same referencenumerals are applied to identical parts in the several gures, and inwhich Fig. 1 is a diagrammatic view in side elevation of an apparatusconstructed in accordance with the invention;

Fig. 2 is a portion of Fig. 1 altered to show a modied form;4

Fig. 3 is another portion of Fig. 1 similarly altered for the same form;and

Fig. 4 is a view similar to Fig. 2 lof anothe modication.

In the embodiment ofthe invention shown inl containing a volatile,inflammable liquid as'one l of its ingredients, e. g. acetone, so thatthe material 2l tends to evolve gases or vapors inflammable and capableof forming explosive mixtures with air. Access may be had to the tankinterior to supply or remove material through a suitable aperture in thetop, as at 22, tightly closed ordinarily, as by the bolted lid 23. Thereis another aperture in the top at 24 with an upstanding collar 25 aroundit and formed'at the top with an -everted ange 26. A flat ring 21 ofinternal diameter somewhat larger than that of the col'- -lar 25 issecured upon the upper face of the flange increase of pressure arisewithin the tank, e. g.

because ofan accidental explosion therein.

A plurality (here four) of spacing members :19, each a vertically boredcylinder as shown ere, stands on the ring 21A and supports a ring 30similar in shape to the ring 21, butpreferably of slightly smallerinternal diameter. On. the

ring 30 rests a dat, horizontal sheet or diaphragm livery member 33, issupported on' the diaphragm4 y 3|, either directly, or as shown, with asealing washer 34, of some suitable material such as ordinary rubberimpregnatedlcloth packing.

A gas delivery nozzle 35\in the top of the trumpet 33 is connected bysuitable piping to the delivery valve 3B oi' a compressed gas tank 31filled with some gas under pressure, e. g. carbon dioxide, nitrogen orthe like, which is noninlammable and tends to prevent or smother fire.The valve 36 is actuatable to open by a'lever 38 operable by suitablemeans such-as the weight 39 attached to the lever.

wire rope 48 secured to one horizontal arm 42 of a three-armed levergenerally indicated at 4|. The weight 39 and cord 40 normally tend toturn the lever 4| clockwise to allow the weight to drop. This isprevented by a detent 45 caught against the upper end oi a verticallyupstanding arm 43 of the lever 4|. The third arm 44 of the lever 4| isformed as a counterpoise weight tending to turn the lever 4|counterclockwise but insufficient to overcome the eiiect of theweight39.

The detent 45 is formed on the outer end of one arm of a lever 46 urgedclockwise by a spring 48 and held against clockwise motion either by thearm 43 of the `lever 4| or by a ilxed stop member 49. The lever 48 maybe actuated to turn counterclockwise by a push rod 50 acting on the arm41 of the lever.

The push rod 50 is secured to one end of a corrugated metal bellows 5|into the other end of which an actuating tube 52 is secured tocommunicate with the otherwise imperforatedly walled interior of thebellows. The tube 52 may preferably be contained within an outer coaxialshield tube 53, and enters the tank 20 at a point above the ordinarymaximum level of the material therein. There the tube is secured to andcommunicates with the interior of a hollow metal bulb 54, here shown ascontained in and supported by a guard cage 55 or heavy wire.

The bulb 54 is of thin walled but relatively rigid metal, preferably ofa metal or metallic alloy, having relatively high heat conductivity andalso not subject materially to corrosion by vapors from the material 2|.In the case or acetone vapors for example, sheet copper will be asuitable material for the bulb. The walls of the bulb are whollyimpertorate except for the sealed in tube 52 and except for a breatherhole. This breather hole is not shown on 'the drawing because it ismerely pinhole through the bulb wall at any convenient location, toosmall to be shown. It plays no part in the actual operation of theinvention, merely acting to prevent false operation of the apparatus bynormal slow changes of atmospheric temperature or barometric pressure,by allowing air to seep slowly into or out of th bulb and thereby keepthe gas pressure within the bulb and bellows equal to the atmosphericpressure outside. However, this breather is too small t0 allow these Thelever is normally held in the valve closing position by a cordorpressures to equalize in case a sudden rise of temperature about thebulb effects a rapid rise u of pressure within if. e

In such a case. before the breather hole can relieve the excess pressurewithin the bulb, this pressure transmitted through the pipe 52 willexpand the bellows 5|, drive the push rod 50 down on the lever arm 41and lift the `detent 45 from its-engagement with the leverarm 43. Thelever 4| will then rotate clockwise under the pull of the cord 40 andweight 39, allowing the weight 39 to turn the lever 38 to open the valve36. The gas released by the valve passes through the connecting pipesand the nozzle 35 into the delivery trumpet 33, vbuilds up suillcientpressure f .sumably under some pressure from the abnormal.

heat in the vicinity of the bulb 54, are thus released and immediatelyso diluted with noninammable, smothering gas from the trumpet 33 thatall danger of explosion or even of re from these vapors is averted.

Ordinarily the parts of the chain of apparatus from the bulb 54 to thevalve lever 38 are s'o proportioned that the system will operate at atemperature about the bulb 54 just a little lower than is required-toexpand the vapors in'the tank -20 enough to rupture the diaphragm 28themselves.

Although for convenience in drawing the gas tank 31 and the mechanismfrom the bellows 5| to the tank valve 36 are shown in closejuxtaposition to the storage tank 28, these will in actual practice belocated at some distance from the storage tank, as suggested by thebreaks shown in the interconnecting pipe lines, perhaps even in anotherroom. Then should external nre menace danger from the storagetank tooimminent to permit of waiting for the automatic actuation, the cord 40may be released. from the lever -arm 42 by means of the knot or handle56 on the upper end of the cord. To this end the lever arm 42 isAforked, the cord passes up through the fork, and the handle 58 rests onthe legs of the fork. With the cord thus detached from the lever, theweight 38 is free to move the lever 38 to open the gas valve.

In the modified form disclosed in Figs. 2 and 3, the bulb 54 is replacedby a thermoelectric device |54 connected through wires |52 replacing thetube 52 to a solenoid |5| whose pullrod |50 actuates the lever arm 41.Both of the arrangements above described operate upon the occurence ofan abnormally high purely pressure responsive device such as a metallicbellows 254 which will shorten under external gas pressure and thus movethe rod 251 'to close an electrical switch 258 and thus actuate lthesolenoid of Fig. 3 upon the occurrence of an excessive pressure ofpredetermined amount within the container.

" While al1 the forms above tdescribed are adapted to provide a blast ofnon-inflammable gas tank 31 could-be replaced by -a source ofvnon-inflammable liquid, especially if the material 2l and its vaporsare soluble or miscible in the particular liquid employed. The nozzle 35would then be formed as the case mightrequire,

to deliver the liquid as foam, spray or in a jetk according to itsnature.

'I'he embodiments shown are illustrative and may be modied and departedfrom in various waysvwithout departing from the spirit and scope of therinvention as pointed out in and limited only by the appended claims.

container.

2. A safety apparatus for a container for materials which may evolvevapors and which container is provided with a relief aperture and meansto close the same, the said apparatus comprsing a nozzle opposed to theaperture and connected through a valve to a supply of non-inflammableuid, and means actuable :by the occurrence in the container of anabnormal condition to open the valve torelease fluid through the nozzleto open the aperture and to surround the same with the non-inammablefluid.

v3. A safety apparatus for a container for materials which may evolvevapors and which container is provided with a relief aperture and meansto close the same, the said apparatus comprising a nozzle opposed to theaperture and connected through a valve to a supply of non-innammablefluid, and temperature responsive means actuable by the occurrence inthe container of anl abnormal temperature to open the valve to re-2,317,836 gas or vapor from the nozzle 35, if desired the apparatuscomprising a nozzle opposed to the aperture and connected through avalve to a supply of non-inflammable fluid, and means actuable 4=by theoccurence in the container of an abnormal condition to openthe valve torelease fluid through the nozzle to rupture the diaphragm and tosurround the aperture with uid.

6. A safety apparatus for afcontanerv for materials which may evolvevapors and which conlease fluid through the nozzle to open the -apertureand tov surround the same with the noniniiammable fluid.

4. A safety apparatus for a container for materials which may evolvevapors and which container is provided with a relief aperture. and meansto close the same, the said apparatus comprising a nozzle opposed to theaperture and connected through a valve to a supply of noninammablefluid, and pressure responsive means actuable by the occurrence in thecontainer of an abnormal pressure to open the valve torelease duidthrough the nozzle to open. the aperture and to surround the same withfluid.

5. A safety apparatus for a container for materials which may evolvevapors and which container is provided with a reliefaperture and arupturable diaphragm to close the same, the said tainer is provided witha relief aperture and a rupturable diaphragm to close the same, the

said apparatus comprising a shatterable dlaphragm spaced from andopposed to the rupturable diaphragm, a fiuid ejection nozzle directedtoward the shatterable diaphragm on the other side thereof from therupturable diaphragm; means including a valve to supply non-infiammableuid .to the nozzle, and means `actuable by the occurrence in thecontainer of an ab-. normal condition to open the valve to release fluidthrough the nozzle to shatter the shatterable diaphragm and project thelfragments thereof to rupture the rupturable diaphragm while the fluidalso surrounds the aperture.

7. A safety apparatus for a container'for materials which may evolvevapors and which container is provided witha relief aperture and arupturable diaphragm to close the same, the said lapparatus comprising ashatterable diaphragm spaced from and opposed to the rupturablediaphragm, a fluid ejection nozzle directed toward the shatterablediaphragm on the other side thereof from the rupturable diaphragm, meansincluding a valve to supply non-infiammable fluid to the nozzle, andtemperature rey sponsive means actua-ble by the occurrence in thecontainer of an abnormal temperature to open the valve to release uidthrough the nozzle to shatter the shatterable diaphragm and project thefragments thereof -to rupture the rupturable diaphragm while the fluidalso surrounds t aperture.

8. A safety apparatus for a container for materialswhich may evolvevapors and which container is provided with a relief aperture and arupturable diaphragm to close the same, the said apparatus comprising ashatterable diaphragm l spaced from and opposed to the rupturablediaphragm, a`uid ejection nozzle directed toward LEO L. WEAVER.

